The present invention relates to a rolling bearing having a resin cage. The rolling bearing is used in an environment stringent in lubricating conditions.
Generally, a rolling bearing used in a vacuum chamber of a semiconductor producing apparatus needs to be used without any lubricant. Hence, a cage having lubrication action are used in the rolling bearing. The cage of this type is subjected to micro-wear by coming into slide contact with at least one of inner and outer races and rolling elements. Particles produced by the micro-wear are transferred to a slide partner to thereby lubricate a slide region and ocher contact regions.
The cage of this type not only needs to be excellent in lubricating characteristic to make the life of the bearing long but also needs to be excellent in dusting characteristic and outgassing characteristic. Therefore, at present, the Applicant of the invention has proposed that a cage using polytetrafluoroethylene (PTFE) as a material is used as the cage. Incidentally, the proposed cage is produced by shaving because PTFE cannot be applied to injection molding.
In the related art, productivity is low because the cage has to be produced by shaving, so that it is pointed out that the cost of production is high. On the other hand, there are various thermoplastic resins as resin materials having lubricating characteristic and capable of being subjected to injection molding. It can be however said that any one of the thermoplastic resins is insufficient in durability because both abrasive wear and torque increase at an early stage.
In the related art, the cage needs to be acclimated to a state in which the cage can fulfill its lubrication action. It can be said that the cage is insufficient in lubricating characteristic particularly at an early stage of use.
In consideration of such circumstances, an object of the invention is to provide a rolling bearing in which improvement in lubricating characteristic and stability in rolling operation can be attained for a long term from an early stage of rotation in spite of use of a resin cage excellent in productivity, low dusting characteristic and outgassing characteristic.
In order to solve the aforesaid object, the invention is characterized by having the following arrangement.
(1) A rolling bearing comprising:
a resin cage which is injection-molded of a mixture material containing a predetermined amount of reinforcing fiber, a predetermined amount of solid lubricant, and one member selected from the group consisting of ethylene-tetrafluoroethylene, polyether-ether-ketone, polyamide-imide alloy, and thermoplastic polyimide; and
a fluid-state lubricating film made of a fluorine-containing polymer having a functional group is deposited on at least one of a rolling surface and a sliding surface of constituent members of the bearing.
(2) The rolling bearing according to (1), wherein potassium titanate whisker is selected as the reinforcing fiber.
(3) The rolling bearing according to (1), wherein at least polytetrafluoroethylene is selected as the solid lubricant.
(4) The rolling bearing according to (1), wherein the three members of polytetrafluoroethylene, molybdenum disulfide and graphite are selected as the solid lubricant.
(5) A rolling bearing comprising:
a resin cage which is injection-molded of a mixture material containing a predetermined amount of reinforcing fiber, a predetermined amount of solid lubricant, and one member selected from the group consisting of ethylene-tetrafluoroethylene, polyether-ether-ketone, polyamide-imide alloy, and thermoplastic polyimide; and
a solid-state lubricating film made of a fluorine-containing polyurethane high-molecular compound is deposited on at least one of a rolling surface and a sliding surface of constituent members of the bearing.
(6) The rolling bearing according to (5), wherein potassium titanate whisker is selected as the reinforcing fiber.
(7) The rolling bearing according to (5), wherein at least polytetrafluoroethylene is selected as the solid lubricant.
(8) The rolling bearing according to (5), wherein the three members of polytetrafluoroethylene, molybdenum disulfide and graphite are selected as the solid lubricant.
(9) The rolling bearing comprising:
a resin cage which is injection-molded of a mixture material containing a predetermined amount of reinforcing fiber, a predetermined amount of solid lubricant, and one member selected from the group consisting of ethylene-tetrafluoroethylene, polyether-ether-ketone, polyamide-imide alloy, and thermoplastic polyimide; and
either a fluid-state lubricating film made of a mixture of a fluorine-containing polymer having a functional group and particles of polytetrafluoroethylene disperses in said fluorine-containing polymer or a solid-state lubricating film made of a mixture of a fluorine-containing polyurethane high-molecular compound and particles of polytetrafluoroethylene dispersed in said fluorine-containing polyurethane high-molecular compound is deposited on at least rolling surfaces and/or sliding surfaces of constituent members of said bearing.
(10) The rolling bearing according to (9), wherein potassium titanate whisker is selected as the reinforcing fiber.
(11) The rolling bearing according to (9), wherein at least polytetrafluoroethylene is selected as the solid lubricant.
(12) The rolling bearing according to (9), wherein the three members of polytetrafluoroethylene, molybdenum disulfide and graphite are selected as the solid lubricant.